Aequorea macrodactyla

Aequorea macrodactyla is a species of hydrozoan in the family Aequoreidae. It was first described by Johann Friedrich von Brandt in 1835.

Description
It can have up to 150 tentacles and grow up to 25 cm.

Bioluminescence
Bioluminescence is a common feature among marine organisms. The luminescent system of A. macrodactyla is similar to a related species, A. victoria, and consists of a 27-kDa green fluorescent protein and the aequorin complex which consists of a 22-kDa apoaequorin, the luminophore coelenterazine, and molecular oxygen. These proteins function together. As calcium binds to coelenterazine, (a bioluminescent molecule in sea life), the molecule oxidizes which results in the release of carbon dioxide and blue light. The blue light emitted from the aequorin activates GFP causing it to emit a green light. The difference between the two organisms is color; A. macrodactyla is brighter, and bolder in color. This is due to a difference in intron length in GFP.